Fire extinguishing gas calculator. Calculation of gas fire extinguishing. Gas fire extinguishing and its undeniable advantages

E.1 The estimated mass of GFFS, which must be stored in the installation, is determined by the formula

where is the mass of fire extinguishing agent intended to create a fire extinguishing concentration in the volume of the room in the absence of artificial air ventilation, determined by the formulas:

For GFFS - liquefied gases, with the exception of carbon dioxide:

For GFFS - compressed gases and carbon dioxide

here - the calculated volume of the protected room, m. The calculated volume of the room includes its internal geometric volume, including the volume of the ventilation, air conditioning, air heating system (up to sealed valves or dampers). The volume of equipment located in the room is not deducted from it, with the exception of the volume of solid (impenetrable) building elements (columns, beams, foundations for equipment, etc.);

Coefficient taking into account leaks of gas extinguishing agent from vessels;

A coefficient that takes into account the loss of gas extinguishing agent through room openings;

Gas density fire extinguishing agent taking into account the height of the protected object relative to sea level for the minimum room temperature, kg/m, determined by the formula

here is the vapor density of the gas fire extinguishing agent at a temperature of 293 K (20 °C) and atmospheric pressure 101.3 kPa;

Minimum air temperature in the protected room, K;

A correction factor that takes into account the height of the object relative to sea level, the values ​​of which are given in Table E.11 of Appendix E;

Standard volume concentration, % (vol.).

The values ​​of standard fire extinguishing concentrations are given in Appendix D.

The mass of GFFS residue in pipelines, kg, is determined by the formula

where is the volume of the entire piping of the installation, m;

The density of the residual fire extinguishing agent at the pressure that exists in the pipeline after the end of the flow of the mass of gaseous fire extinguishing agent into the protected room;

The product of the remaining GFFS in the module, which is accepted according to the TD per module, kg, by the number of modules in the installation.

Note - For liquid flammable substances not listed in Appendix E, the standard volumetric fire extinguishing concentration of GFFS, all components of which are in the gas phase under normal conditions, can be determined as the product of the minimum volumetric fire extinguishing concentration by a safety factor equal to 1.2 for all GFFS , with the exception of carbon dioxide. For SO, the safety factor is 1.7.

For GFFS that are in the liquid phase under normal conditions, as well as mixtures of GFFS, at least one of the components of which is in the liquid phase under normal conditions, the standard fire extinguishing concentration is determined by multiplying the volumetric fire extinguishing concentration by a safety factor of 1.2.

Methods for determining the minimum volumetric fire extinguishing concentration and fire extinguishing concentration are set out in GOST R 53280.3.

E.2 The coefficients of equation (E.1) are determined as follows.

E.2.1 Coefficient taking into account leaks of gas extinguishing agent from vessels 1.05.

E.2.2 Coefficient taking into account the loss of gas extinguishing agent through room openings:

where is a parameter that takes into account the location of openings along the height of the protected room, m s.

The numerical values ​​of the parameter are selected as follows:

0.65 - when openings are located simultaneously in the lower (0-0.2) and upper zones of the room (0.8-1.0) or simultaneously on the ceiling and floor of the room, and the areas of the openings in the lower and upper parts are approximately equal and constitute half of the total area of ​​the openings; 0.1 - when the openings are located only in the upper zone (0.8-1.0) of the protected room (or on the ceiling); 0.25 - when the openings are located only in the lower zone (0-0, 2) the protected room (or on the floor); 0.4 - with an approximately uniform distribution of the area of ​​openings over the entire height of the protected room and in all other cases;

Room leakage parameter, m,

where is the total area of ​​openings, m;

Room height, m;

Standard time for supplying GFFS to the protected premises, s.

E.3 Extinguishing fires of subclass A (except for smoldering materials specified in 8.1.1) should be carried out in rooms with a leakage parameter of no more than 0.001 m.

The mass value for extinguishing fires of subclass A is determined by the formula

where is the mass value for the standard volumetric concentration when extinguishing n-heptane, calculated using formulas (2) or (3);

A coefficient that takes into account the type of combustible material.

The coefficient values ​​are taken equal to: 1.3 - for extinguishing paper, corrugated paper, cardboard, fabrics, etc. in bales, rolls or folders; 2.25 - for premises with the same materials, to which access for firefighters after the end of the AUGP operation is excluded. For other fires of subclass A, except those specified in 8.1.1, the value is assumed to be 1.2.

In this case, it is allowed to increase the standard time for supplying GFFS by a factor.

If the estimated quantity of GFFS is determined using a factor of 2.25, the GFFS reserve can be reduced and determined by calculation using a factor of 1.3.

You should not open the protected room to which access is permitted, or break its tightness in any other way within 20 minutes after the activation of the AUGP (or until the fire department arrives).

Appendix G

Methodology for calculating the mass of gaseous fire extinguishing agent for mouthsnew gas fire extinguishing technology for extinguishing by volumetric method

1. The estimated mass of GFFS, which must be stored in the installation, is determined by the formula

Where
- the mass of fire extinguishing agent intended to create a fire extinguishing concentration in the volume of the room in the absence of artificial air ventilation is determined by the formulas:

for GFFS - liquefied gases, with the exception of carbon dioxide

; (2)

for GOTV - compressed gases and carbon dioxide

Where - estimated volume of the protected room, m3.

The calculated volume of the room includes its internal geometric volume, including the volume of the ventilation, air conditioning, and air heating systems (up to sealed valves or dampers). The volume of equipment located in the room is not deducted from it, with the exception of the volume of solid (impenetrable) building elements (columns, beams, foundations for equipment, etc.);

- coefficient taking into account leaks of gas extinguishing agent from vessels;
- coefficient taking into account the loss of gas extinguishing agent through room openings; - density of the gas extinguishing agent, taking into account the height of the protected object relative to sea level for the minimum room temperature , kg  m -3, determined by the formula

, (4)

Where - vapor density of gas extinguishing agent at temperature = 293 K (20 С) and atmospheric pressure 101.3 kPa;
- minimum temperature air in the protected room, K; - correction factor taking into account the height of the object relative to sea level, the values ​​of which are given in Table 11 of Appendix 5;
- standard volume concentration, % (vol.).

The values ​​of standard fire extinguishing concentrations () are given in Appendix 5.

Weight of GFFS residue in pipelines
, kg, determined by the formula

, (5)

Where
- volume of the entire installation piping, m 3 ;
- density of the fire extinguishing agent residue at the pressure that exists in the pipeline after the end of the flow of the mass of gaseous fire extinguishing agent into the protected room.

- product of the remainder of the GFFS in the module ( M b), which is accepted according to the TD per module, kg, per number of modules in the installation.

Note. For liquid flammable substances not listed in Appendix 5, the standard volumetric fire extinguishing concentration of GFFS, all components of which are in the gas phase under normal conditions, can be determined as the product of the minimum volumetric fire extinguishing concentration by a safety factor equal to 1.2 for all GFFS, for except for carbon dioxide. For CO 2 the safety factor is 1.7.

For GFFS that are in the liquid phase under normal conditions, as well as mixtures of GFFS, at least one of the components of which is in the liquid phase under normal conditions, the standard fire extinguishing concentration is determined by multiplying the volumetric fire extinguishing concentration by a safety factor of 1.2.

Methods for determining the minimum volumetric fire extinguishing concentration and fire extinguishing concentration are set out in NPB 51-96 *.

1.1. The coefficients of equation (1) are determined as follows.

1.1.1. Coefficient taking into account leakage of gas extinguishing agent from vessels:

.

1.1.2. Coefficient taking into account the loss of gas extinguishing agent through room openings:

, (6)

Where
- parameter that takes into account the location of openings along the height of the protected room, m 0.5  s -1.

The numerical values ​​of the parameter are selected as follows:

0.65 - when openings are located simultaneously at the bottom (0 - 0.2)
and the upper zone of the room (0.8 - 1.0) or simultaneously on the ceiling and on the floor of the room, and the areas of the openings in the lower and upper parts are approximately equal and constitute half of the total area of ​​the openings; = 0.1 - when openings are located only in the upper zone (0.8 - 1.0) of the protected room (or on the ceiling); = 0.25 - when openings are located only in the lower zone (0 - 0.2) of the protected room (or on the floor); = 0.4 - with an approximately uniform distribution of the area of ​​openings over the entire height of the protected room and in all other cases.

- room leakage parameter, m -1,

Where
- total area of ​​openings, m2.

Room height, m; - standard time for supplying GFFS to the protected premises.

1.1.3. Extinguishing fires of subclass A 1 (except for smoldering materials specified in clause 7.1) should be carried out in rooms with a leakage parameter of no more than 0.001 m -1.

The value of mass M p for extinguishing fires of subclass A 1 is determined by the formula

M p = K 4. M r-hept,

where M p-hept is the value of the mass M p for the standard volumetric concentration of CH when extinguishing n-heptane, calculated using formulas 2 or 3;

K 4 is a coefficient that takes into account the type of combustible material. The values ​​of the K 4 coefficient are taken equal to: 1.3 – for extinguishing paper, corrugated paper, cardboard, fabrics, etc. in bales, rolls or folders; 2.25 - for premises with the same materials, to which access of firefighters is excluded after the end of the AUGP operation, while the reserve stock is calculated at a K 4 value equal to 1.3.

The supply time of the main stock of GFFS at a K 4 value of 2.25 can be increased by 2.25 times. For other fires of subclass A 1, the value of K 4 is taken equal to 1.2.

You should not open the protected room or break its tightness in any other way for at least 20 minutes (or until the fire department arrives).

When opening premises, primary fire extinguishing means must be available.

For premises in which access to fire departments is excluded after the end of the AUGP operation, CO 2 should be used as a fire extinguishing agent with a coefficient of 2.25.

1. Average pressure in an isothermal tank during the supply of carbon dioxide ,MPa, is determined by the formula

, (1)

Where - pressure in the tank during carbon dioxide storage, MPa; - pressure in the tank at the end of the release of the estimated amount of carbon dioxide, MPa, is determined according to Figure 1.

2. Average carbon dioxide consumption

, (2)

Where
- estimated amount of carbon dioxide, kg; - standard carbon dioxide supply time, s.

3. Inner diameter of the supply (main) pipeline , m, is determined by the formula

Where k 4 - multiplier, determined according to table 1; l 1 - length of the supply (main) pipeline according to the project, m.

Table 1

4. Average pressure in the supply (main) pipeline at the point of its entry into the protected room

Where l 2 - equivalent length of pipelines from the isothermal tank to the point at which the pressure is determined, m:

, (5)

Where - the sum of the resistance coefficients of pipeline fittings.

5. Medium pressure

, (6)

Where R 3 - pressure at the point of entry of the supply (main) pipeline into the protected room, MPa; R 4 - pressure at the end of the supply (main) pipeline, MPa.

6. Average flow rate through nozzles Q m, kg  s -1, determined by the formula

where is the flow coefficient through the nozzles; A 3 - area of ​​the nozzle outlet, m2; k 5 - coefficient determined by the formula

7. Number of nozzles determined by the formula

8. Inner diameter of distribution pipeline , m, is calculated from the condition

, (9)

Where - diameter of the nozzle outlet, m.

R

R 1 =2,4

reservoir at the end of the release of the calculated amount of carbon dioxide

Note. Relative mass of carbon dioxide determined by the formula

,

Where - initial mass of carbon dioxide, kg.

Appendix 7

Methodology for calculating the opening area for releasing excess pressure in rooms protected by gas fire extinguishing installations

Opening area for releasing excess pressure , m 2, is determined by the formula

,

Where - maximum permissible excess pressure, which is determined from the condition of maintaining the strength of the building structures of the protected premises or the equipment placed in it, MPa; - atmospheric pressure, MPa; - air density under operating conditions of the protected premises, kg  m -3; - safety factor taken equal to 1.2; - coefficient taking into account the change in pressure when it is supplied;
- time of supply of GFFS, determined from hydraulic calculation, s;
- area of ​​permanently open openings (except for the discharge opening) in the enclosing structures of the room, m2.

Values ​​of quantities , , are determined in accordance with Appendix 6.

For GOTV - liquefied gases the coefficient TO 3 =1.

For GOTV - compressed gases the coefficient TO 3 is taken equal to:

for nitrogen - 2.4;

for argon - 2.66;

for the Inergen composition - 2.44.

If the value of the expression on the right side of the inequality is less than or equal to zero, then an opening (device) for relieving excess pressure is not required.

Note. The opening area value was calculated without taking into account the cooling effect of liquefied gas, which may lead to a slight reduction in the opening area.

General provisions for the calculation of modular type powder fire extinguishing installations.

1. The initial data for the calculation and design of installations are:

geometric dimensions of the room (volume, area of ​​enclosing structures, height);

area of ​​open openings in enclosing structures;

operating temperature, pressure and humidity in the protected area;

list of substances, materials located in the room, and their indicators fire danger, the corresponding fire class according to GOST 27331;

type, magnitude and fire load distribution scheme;

availability and characteristics of ventilation, air conditioning, air heating systems;

characteristics and arrangement of technological equipment;

the presence of people and their evacuation routes.

technical documentation for modules.

2. Installation calculation includes determining:

number of modules intended for fire extinguishing;

evacuation times, if any;

installation operating time;

the necessary supply of powder, modules, components;

type and required quantity detectors (if necessary) to ensure the operation of the installation, signaling and starting devices, power supplies to start the installation (for cases according to clause 8.5).

Methodology for calculating the number of modules for modular powder fire extinguishing installations

1. Extinguishing the protected volume

1.1. Extinguishing the entire protected volume

The number of modules to protect the volume of the room is determined by the formula

, (1)

Where
- number of modules required to protect the premises, pcs.; - volume of the protected room, m 3 ; - the volume protected by one module of the selected type is determined according to the technical documentation (hereinafter referred to as the application documentation) for the module, m 3 (taking into account the spray geometry - the shape and dimensions of the protected volume declared by the manufacturer); = 11.2 - coefficient of unevenness of powder spraying. When placing spray nozzles on the border of the maximum permissible (according to the documentation for the module) height To = 1.2 or determined from the documentation for the module.

- safety factor taking into account the shading of a possible source of fire, depending on the ratio of the area shaded by the equipment , to the protected area S y, and is defined as:

at
,

Shading area is defined as the area of ​​the part of the protected area where the formation of a source of fire is possible, to which the movement of the powder from the spray nozzle in a straight line is blocked by structural elements impenetrable to the powder.

At
It is recommended to install additional modules directly in a shaded area or in a position that eliminates shading; if this condition is met k is taken equal to 1.

- coefficient that takes into account the change in the fire extinguishing efficiency of the powder used in relation to the flammable substance in the protected area in comparison with A-76 gasoline. Determined from Table 1. In the absence of data, determined experimentally using VNIIPO methods.

- coefficient taking into account the degree of leakage of the room. = 1 + V F neg , Where F neg = F/F pom- ratio of the total leakage area (openings, cracks) F to the general surface of the room F pom, coefficient IN determined according to Figure 1.

IN

20

Fн/ F , Fв/ F

Figure 1 Graph for determining coefficient B when calculating the coefficient.

F n- area of ​​leakage in the lower part of the room; F V- area of ​​leakage in the upper part of the room, F - total area of ​​leakage (openings, cracks).

For pulse fire extinguishing installations, the coefficient IN can be determined from the documentation for the modules.

1.2. Local fire extinguishing by volume

The calculation is carried out in the same way as when extinguishing throughout the entire volume, taking into account paragraphs. 8.12-8.14. Local volume V n, protected by one module, is determined according to the documentation for the modules (taking into account the spray geometry - the shape and dimensions of the local protected volume declared by the manufacturer), and the protected volume V h is defined as the volume of an object increased by 15%.

For local fire extinguishing by volume it is taken =1.3, it is allowed to take other values ​​given in the documentation for the module.

2. Fire extinguishing by area

2.1. Extinguishing over the entire area

The number of modules required for fire extinguishing over the area of ​​the protected premises is determined by the formula

For local extinguishing over an area, =1.3 is taken, other values ​​are allowed To 4 given in the documentation for the module or justified in the project.

As S n the area of ​​the maximum rank of a class B fire, the extinguishing of which is provided by this module, can be taken (determined according to the documentation for the module, m 2).

Note. If the number of modules of fractional numbers is obtained when calculating the number of modules, the next in order larger integer number is taken as the final number.

When protecting by area, taking into account the design and technological features of the protected object (with justification in the design), it is allowed to launch modules using algorithms that provide area-by-area protection. In this case, the protected area is taken to be part of the area allocated by design (driveways, etc.) or structural non-combustible (walls, partitions, etc.) solutions. The operation of the installation must ensure that the fire does not spread beyond the protected area, calculated taking into account the inertia of the installation and the speed of fire spread (for specific type flammable materials).

Table 1.

Coefficient comparative effectiveness of fire extinguishing agents

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Currently gas fire extinguishing refers to efficient, environmentally friendly and universal method fire fighting on early stage occurrence of a fire.

Calculation of the installation of gas fire extinguishing systems is widely used at facilities where the use of other fire fighting systems – powder, water, etc. – is undesirable.

Such objects include premises with electrical equipment, archives, museums, exhibition halls, warehouses with those there explosive substances etc.

Gas fire extinguishing and its undeniable advantages

In the world, including Russia, gas fire extinguishing has become one of the widely used methods of eliminating the source of fire due to a number of undeniable advantages:

• minimization negative influence on environment due to the release of gases;
• ease of removing gases from the room;
• precise distribution of gas over the entire area of ​​the room;
• non-damage to property, valuables and equipment;
• functioning over a wide temperature range.

Why is a gas fire extinguishing calculation necessary?

To select a particular installation for a room or facility, a clear calculation of gas fire extinguishing is required. Thus, a distinction is made between centralized and modular complexes. The choice of one type or another depends on the number of premises that need to be protected from fire, the area of ​​the facility and its type.

Taking these parameters into account, gas fire extinguishing is calculated, with mandatory consideration of the mass of gas required to eliminate the source of fire in a certain area. For such calculations we use special techniques, taking into account the type of fire extinguishing agent, the area of ​​the entire room and the type of fire-fighting installation.

For calculations, the following parameters must be taken into account:

• room area (length, ceiling height, width);
• object type (archive, server rooms, etc.);
• the presence of open openings;
• type of flammable substances;
• fire hazard class;
• degree of distance of the security console from the premises.

The need to calculate gas fire extinguishing

Fire extinguishing calculations – preliminary stage before installing a gas fire extinguishing system at the site. To ensure the safety of people and the safety of property, it is necessary to carry out a clear calculation of the equipment.

The validity of the calculation of gas fire extinguishing and subsequent installation at the facility is determined regulatory documentation. The use of this system in server rooms, archives, museums and data centers is mandatory. In addition, such installations are installed in car parks closed type, in repair shops, warehouse-type premises. The calculation of fire extinguishing directly depends on the size of the room and the type of goods stored in it.

The undeniable advantage of gas fire extinguishing over powder or water installations is its lightning-fast response and operation in the event of a fire, while objects or materials in the room are reliably protected from the negative effects of fire extinguishing agents.

At the design stage, the amount of fire extinguishing agent required to extinguish the fire is calculated. The further functioning of the complex depends on this stage.

Fill out the form fields to find out the cost of a gas fire extinguishing system.

The preference of domestic consumers in favor of effective fire extinguishing, in which gaseous fire extinguishing agents are used to eliminate electrical fires and class A, B, C fires (according to GOST 27331), is explained by the advantages of this technology. Fire extinguishing using gas, in comparison with the use of other fire extinguishing agents, is one of the most non-aggressive ways to eliminate fires.

When calculating the fire extinguishing system, the requirements are taken into account regulatory documents, the specifics of the object, and also determine the type gas installation– modular or centralized (possibility of extinguishing fire in several rooms).
An automatic gas fire extinguishing installation consists of:

• cylinders or other containers intended for storing gaseous fire extinguishing agent,
• pipelines and directional valves that provide the supply of fire extinguishing agent, gas (freon, nitrogen, CO2, argon, SF6 gas, etc.) in a compressed or liquefied state to the source of fire,
• detection and control devices.

When submitting an application for the supply, installation of equipment or the entire range of services, clients of our company “KompaS” are interested in the estimate for gas fire extinguishing. Indeed, information that this type is one of the “expensive” methods of extinguishing a fire, which is fair. However, an accurate calculation of the fire extinguishing system, made by our specialists taking into account all conditions, demonstrates that automatic installation gas fire extinguishing in practice may turn out to be the most effective and beneficial for the consumer.

Fire extinguishing calculation - the first stage of installation design

The main task for those who order gas fire extinguishing is to calculate the cost of the mass of gas that will be required to extinguish the fire in the room. As a rule, fire extinguishing is calculated by area (length, height, width of the room); in certain conditions, other object parameters may be required:

• type of room (server room, archive, data center);
• presence of open openings;
• if there is a false floor or false ceiling, indicate their heights;
• minimum room temperature;
• types of combustible materials;
• type of fire extinguishing agent (optional);
• explosion and fire hazard class;
• remoteness of the control room/security console from the protected premises.

Clients of our company can pre-.

1. The estimated mass of GFFS M_g, which must be stored in the installation, is determined by the formula

M = K, (1)

where M is the mass of GFFS intended to create in volume

premises of fire extinguishing concentration in the absence of artificial

air ventilation is determined by the formulas:

for GFFS - liquefied gases, with the exception of carbon dioxide

M = V x po x (1 + K) x ──────────; (2)

р р 1 2 100 - C

for GOTV - compressed gases and carbon dioxide

M = V x po x (1 + K) x ln ──────────, (3)

р р 1 2 100 - C

where V is the estimated volume of the protected room, m3.

The calculated volume of the room includes its internal geometric volume, including the volume of the ventilation, air conditioning, and air heating systems (up to sealed valves or dampers). The volume of equipment located in the room is not deducted from it, with the exception of the volume of solid (impenetrable) building elements (columns, beams, foundations for equipment, etc.); K_1 - coefficient taking into account leaks of gas fire extinguishing agent from vessels; K_2 - coefficient taking into account the loss of gas extinguishing agent through room openings; ro_1 - density of the gas fire extinguishing agent, taking into account the height of the protected object relative to sea level for the minimum room temperature T_m, kg x m(-3), determined by the formula

rho = rho x ──── x K, (4)

where po_0 is the vapor density of the gas fire extinguishing agent at temperature T_0 = 293 K (20°C) and atmospheric pressure 101.3 kPa; T_m - minimum air temperature in the protected room, K; K_3 - correction factor taking into account the height of the object relative to sea level, the values ​​of which are given in table 11 appendices 5; S_n - standard volume concentration, % (vol.).

The values ​​of standard fire extinguishing concentrations С_н are given in Appendix 5.

The mass of the remaining GFFS in pipelines M_tr, kg, is determined by the formula

M = V x rho, (5)

tr tr GOTV

where V is the volume of the entire installation piping, m3;

po is the density of the GFFS residue at the pressure that exists in

pipeline after the expiration of the mass of gas fire extinguishing agent

substances M into the protected area; M x n - product of the remainder of the GFSR in

module (M), which is accepted according to TD per module, kg, per quantity

There are n modules in the installation.

Note. For liquid flammable substances not listed in Appendix 5, the standard volumetric fire extinguishing concentration of GFFS, all components of which are in the gas phase under normal conditions, can be determined as the product of the minimum volumetric fire extinguishing concentration by a safety factor equal to 1.2 for all GFFS, with the exception of carbon dioxide. For CO2, the safety factor is 1.7.

For GFFS that are in the liquid phase under normal conditions, as well as mixtures of GFFS, at least one of the components of which is in the liquid phase under normal conditions, the standard fire extinguishing concentration is determined by multiplying the volumetric fire extinguishing concentration by a safety factor of 1.2.

Methods for determining the minimum volumetric fire extinguishing concentration and fire extinguishing concentration are set out in NPB 51-96*.

1.1. Equation coefficients (1) are defined as follows.

1.1.1. Coefficient taking into account leakage of gas extinguishing agent from vessels:

1.1.2. Coefficient taking into account the loss of gas extinguishing agent through room openings:

K = P x delta x tau x square root (H), (6)

where P is a parameter that takes into account the location of openings along the height of the protected room, m(0.5) x s(-1).

The numerical values ​​of the parameter P are selected as follows:

P = 0.65 - when openings are located simultaneously in the lower (0-0.2) N and upper zones of the room (0.8-1.0) N or simultaneously on the ceiling and on the floor of the room, and the areas of the openings in the lower and upper the parts are approximately equal and make up half the total area of ​​the openings; P = 0.1 - when openings are located only in the upper zone (0.8-1.0) N of the protected room (or on the ceiling); P = 0.25 - when openings are located only in the lower zone (0-0.2) N of the protected room (or on the floor); P = 0.4 - with an approximately uniform distribution of the area of ​​openings over the entire height of the protected room and in all other cases;

delta = ───────── - room leakage parameter, m(-1),

where the sum F_H is the total area of ​​the openings, m2, H is the height of the room, m; tau_pod - standard time for supplying GFFS to the protected premises, s.

1.1.3. Extinguishing fires of subclass A_1 (except for smoldering materials specified in clause 7.1) should be carried out in rooms with a leakage parameter of no more than 0.001 m(-1).

The value of mass М_р for extinguishing fires of subclass A_i is determined by the formula

r 4 r-hept

where M is the value of mass M for the standard volume concentration C

r-hept r n

when extinguishing n-heptane, calculated by formulas (2) or (3) ;

K is a coefficient that takes into account the type of combustible material.

The values ​​of the coefficient K_4 are taken equal to: 1.3 - for extinguishing paper, corrugated paper, cardboard, fabrics, etc. in bales, rolls or folders; 2.25 - for premises with the same materials, to which access of firefighters is excluded after the end of the AUGP operation, while the reserve stock is calculated at a K_4 value of 1.3.

The supply time of the main stock of GFFS with a K_4 value of 2.25 can be increased by 2.25 times. For other fires of subclass A_1, the value of K_4 is taken equal to 1.2.

You should not open the protected room to which access is permitted, or break its tightness in any other way within 20 minutes after the activation of the AUGP (or until the fire department arrives).